Electrodes including support filament with collar stop

Abstract

An electrode including structures configured to prevent an intercalation layer from detaching from the electrode and/or a structure configured to create a region on the electrode having a lower concentration of intercalation material. The electrode includes a support filament on which the intercalation layer is disposed. The support filament optionally has nano-scale dimensions.

What is claimed is: 
     
       1. An electrode comprising:
 a substrate; 
 a support filament coupled to the substrate, the support filament including a nano-filament; 
 an intercalation layer including a donor acceptor material configured to receive a reactant of an electrochemical reaction, the donor acceptor material being disposed along the length of the support filament, a thickness of the intercalation layer being less than a length of the support filament; 
 a region of the intercalation layer proximate to the substrate and including a lower amount of donor acceptor material relative to a region of the intercalation layer distal to the substrate; and, 
 a collar stop disposed along the length of the support filament and configured to generate the region of the intercalation layer including a lower amount of the donor acceptor material. 
 
     
     
       2. The electrode of  claim 1 , wherein the support filament includes a carbon nano-tube or a carbon nano-fiber, or a nano-wire. 
     
     
       3. The electrode of  claim 1 , wherein the intercalation layer includes silicon, tin or germanium. 
     
     
       4. The electrode of  claim 1 , wherein the amount of intercalation material, in weight per unit area of support filament, in the region of the intercalation layer including a lower amount of donor acceptor includes less than 75% of the donor acceptor material in the region distal to the substrate. 
     
     
       5. The electrode of  claim 1 , wherein the amount of intercalation material, in weight per unit area of support filament, in the region of the intercalation layer including a lower amount of donor acceptor includes less than 50% of the donor acceptor material in the region distal to the substrate. 
     
     
       6. The electrode of  claim 1 , further comprising a support collar configured to prevent the intercalation layer from separating from the support filament. 
     
     
       7. The electrode of  claim 1 , further comprising a support cap configured to prevent the intercalation layer from separating from the support filament. 
     
     
       8. The electrode of  claim 1 , wherein the intercalation layer is p+ or n+ doped. 
     
     
       9. The electrode of  claim 1 , further comprising a seed layer disposed between the substrate and the support filament and configured to couple the support filament to the substrate. 
     
     
       10. The electrode of  claim 1 , wherein the support filament includes more than one support collar. 
     
     
       11. The electrode of  claim 1 , further comprising a carbide layer, an oxide layer or a nitride layer on a surface of the intercalation layer. 
     
     
       12. The electrode of  claim 1 , wherein the intercalation layer includes a metal. 
     
     
       13. The electrode of  claim 1 , wherein a surface of the intercalation layer is passivated. 
     
     
       14. A battery comprising:
 a first electrode; and 
 a second electrode comprising
 a substrate, 
 a support filament coupled to the substrate, the support filament including a nano-filament, 
 an intercalation layer configured to receive a reactant of an electrochemical reaction, the intercalation layer being disposed on the support filament, and a collar stop configured for creating regions of the intercalation layer having different thicknesses along the length of the support filament. 
 
 
     
     
       15. The battery  claim 14 , wherein second electrode is configured to operate as an anode. 
     
     
       16. The battery of  claim 14 , further comprising means for preventing the intercalation layer from sliding off of the support filament. 
     
     
       17. The battery of  claim 14 , further comprising means for increasing the conductivity of the intercalation layer. 
     
     
       18. The electrode of  claim 1 , wherein the support filament includes a carbon nano-tube or a carbon nano-fiber. 
     
     
       19. The electrode of  claim 12 , where in the metal is selected to increase the conductivity of the intercalation layer. 
     
     
       20. The electrode of  claim 6 , wherein the support collar has a conical or triangular cross section. 
     
     
       21. The electrode of  claim 6 , wherein the support collar has a tapered shape. 
     
     
       22. The electrode of  claim 1 , wherein the intercalation layer includes a metal and an oxide. 
     
     
       23. The battery of  claim 14 , further comprising more than one support collar configured for creating regions of different thicknesses of the intercalation layer. 
     
     
       24. A battery comprising:
 a first electrode; and 
 a second electrode comprising
 a substrate, 
 support filaments grown from initiation sites on the substrate, the support filaments including nano-filaments and more than one support collar, wherein a ratio between a height of the support filaments above the substrate and an average separation between the support filament initiation sites is 5:1 or greater; and 
 an intercalation layer configured to receive a reactant of an electrochemical reaction, the intercalation layer being disposed on the support filament. 
 
 
     
     
       25. The battery of  claim 24 , wherein the intercalation layer includes a metal and an oxide. 
     
     
       26. The battery of  claim 24 , wherein the intercalation layer includes silicon. 
     
     
       27. The battery of  claim 24 , wherein the intercalation layer includes silicon, a metal and an oxide. 
     
     
       28. The battery of  claim 24 , wherein the more than one support collar are configured to generate regions along the support filament having different thicknesses of intercalation layer. 
     
     
       29. The battery of  claim 24 , wherein the more than one support collar are configured to support attachment of the intercalation layer to the support filament. 
     
     
       30. The electrode of  claim 1 , wherein the support filament comprises a multi-walled carbon nanotube. 
     
     
       31. The battery of  claim 24 , wherein the ratio between the height of the support filaments above the substrate and the average separation between the support filament initiation sites is 10:1 or greater. 
     
     
       32. The electrode of  claim 1 , further comprising a support collar disposed along the length of the support filament where in the support collar has a support collar height that is less than or equal to 50 nanometers. 
     
     
       33. The electrode of  claim 1 , wherein the support filament includes regions that are at least 2.5% thicker than other regions of the support filament. 
     
     
       34. The electrode of  claim 1 , wherein a thickness of the intercalation layer is less than half an average separation distance between adjacent support filaments. 
     
     
       35. The electrode of  claim 1 , wherein the support filament is one of a plurality of aligned support filaments. 
     
     
       36. The battery of  claim 14 , wherein the intercalation layer has a deposited thickness, perpendicular to the length of the support filament, of less than or equal to 4 micrometers.